Hello. Im a finisher specifically in the feild of stairs and handrailings. As the finisher we are required to complete a full sanding prior to finishing. Unfortunatly the installers will not properly sand the nosings before mounting the spindles, leaving us to sand out cross grains and deveations by hand. I have tried detail sanders but the all seem to leave “z” pattern sanding marks. Would anyone know of a mechanical sander narrow enough to get between spindles.

I have used an oscillating multi-tool. cut the teeth off an old blade cut some sticky backed sand paper to size and go to it.I do believe this is the only place I have found that a variable speed model will be useful. Running at full speed it is possible to start a friction fire if stay in one place too long.